Effects of climate change on heating and cooling degree days and potential energy demand in the household sector of China

Future changes of heating and cooling degree days (HDD and CDD) in the 21st century over mainland China are projected with a regional climate model to investigate the potential effects of climate change on energy demand in the household sector. Validation of the model shows a good performance in reproducing the spatial distribution, magnitude and interannual variability of the present day HDD and CDD. Significant decreases in HDD and increases in CDD are projected under the warming. These are further weighted by population projections for a first-order assessment of future changes in energy demand. A larger decrease in population-weighted regional mean HDD compared to the increase in CDD is projected, indicating a decrease of about 15% in potential energy demand for different periods and scenarios in the future. In addition, the simulations show amarked spatial heterogeneity in the change in energy demand. Specifically, we find increases in both heating and cooling demand in parts of northern China due to the increased population there, an increase in cooling demand in the south and decreases in heating demand in the northernmost and western regions. Furthermore, a seasonal shift occurs, with increasing demand in summer and a decrease in winter. Finally, when the future reference temperatures for household heating and cooling change from standards currently used in China to values closer to those in Europe and the USA, potentially large increases in energy demand (similar to 80%) are expected, illustrating the importance of policy decisions concerning household heating and cooling.